Telephone metering system



Oct. 14, 1930;

' w. WICARPENTER ET Al- TELEPHONE METERING SYSTEM Filed May 31, 1929 /NVE N TORS 4 Sheets-Sheet l l I I I I l I W CARPENTER L. H. Jamvs0- Oct.14, 1.930. w, w, CARPENTER Er AL 1,778,309

' TELEPHONE METERING SYSTEM Filed May 53m 1929 4 Sheets-Sheet 2 w m h Nf m \mw mN SQEW W 1 M www N A TTOHNE) 0a. 14, 1930. v w. w. CARPENTER ETAL 1,778,309

TELEPHONE METERING SYSTEM Filed May 31, 1929 4 Sheets-Sheet '3 WCARPENTER WVENTOR" L. H. Jam/501v '4 7' TORNE) Oct. 14, 1930. E w, w,CARPENTER ET AL 1,778,309

TELEPHONE METERING SYSTEM Filed May 31, 1929 4 Sheets-Sheet 4 W WCARPENTER WVENTOHS. L. hi JOHNSON ATTORNEK Patented Oct. 14, 1930 umrel) STATES PATENT *oFrrcE WARREN w. CARPENTER, or ennnns viLtA en, NEWYORK, AND LEWIS) ioHNs'oN,

on MAnrso NEW JERSEY, AssrG ons TO BELL TELEPHONE LABORATORIES, 1N-oonroan'rn'n, or NEVI Yon-K, N. Y., A CORPORATION on NEW YORK TELEPHONEMETERING SYSTEM Application filed May 31,

This invention relates to dial telephone systems, and more particularlyto metering calls on multi-party telephone lines. The object ofthe'invention is increased economy and ethciency in the apparatusnecessary for this purpose. 7

The embodiment of the invention chosen for the purpose of illustrationcomprises a meter control c rcuit common to the hnes apby Way of thedistrict selector and line finder .to the metering terminal. After ameasured interval the meter control equipment is dis connectedjirom theselector. The control equipment is so arranged that in the case of anindividual line Where the meter is connected directly to the meteringterminal, in which case no registration is set up in the districtselector, application of metering current is rendered independent of theconnectirg relays. Likewise means is provided to discriminate betweenthe condition where the lack of registration is due to the calling linebeing an individual line and that due to a fault in the setting up ofthe registration. In the latter case the circuit is arranged to indicateon meter that no registration was made and scans is also provided in theselector whereby this no registration condition can be to operate analarm,

The invention will be more clearly understood trom a consideration ofthe following description in connection with the attached drawings inwhich 1 shows a portion of a district selector, .Fig, 2 shows afour-party line, an individual line,1and the common meter controlequip1nent,,Fig. 3 shows one complete party identification circuit, Fig.4 shows 1929. Serial No. 367,259.

portions of two other identification circuits, and Fig. 5 is a diagramindicating the manner in which the other figures should be arranged,

Briefly, when a call is initiated thecalling line is associated with adistrict selector by any suitable means, for example, a line finder. Thedistrict selector is then associated with an idle sender and the wantedline number is recorded in the sender which thereupon controls theselective operations of the district selector and other switches..lVh'en selections have been completed a relay is operated whichconnects an idle identification circuit with the calling line. Theoperation of this relay connects a network in ilel with a section of thetalking circuit as 1:; extends through, the district selector and thenopens the talking circuit to insert the network therein. Theidentification circuit then connects a relay to both sides of the linein parallel to determine whether the substation calling is groundedandthen in effect applies battery first to one side of the line and thento the other to operate the polarized relay at the substation which, byits response, determines the registration. Following the registrationthe line is reclosed and the identification circuit isdisconnected fromthe selector. When the called subscrib er answers and the charge relayoperates as an indication that the call has been successful, a metercontrol circuit is associated with the dist selector under the controlof the registra ion set up by the identiiicruzion circuit. The meters ofthe corresponding party of all lines located on the same frame areconnected to the respective metering terminals of the line. For example,it the calling substation were substa on #1, thenthe #1 meter for everyparty line appoaringin the same panel would be connected to the meteringterminal. of the corresponding line. This operation initiates theapplication of metering current to the metering terminal for a measuredinterval after which the e rrent is removed and the meter controlcircuit disconnected from the district selector.

i that the subscriber at substaceiver from the switchhook at thesubstation actuates the line relay 100, thus initiating the operation ofa trip, start and link circuit. These circuits in turn bring about theoperation of a partlcular line tinder LI1Cl'dlS- trict selector for thepurpose of extending the call. The line finder, for example line fmder101, connects with the calling. line,

after which theline is associated with a sender. The operation ofthedial' on the calling line registers the number of the wantedsubscriber in the sender in accordance with which the sender controlsthe operation of the district selector 102 and other switch-- show ordescribe the apparatus and its func- 1710115111 detail. Reference'ishereby made to U. S. Patent 1,589,402, granted January 22,

1926 to O. H. Kopp, for a detailed descrip tion of the establishment ofa connection through equipment'of the type shown.

'As set forth in the above identified patent, the operations of the linefinder 101 and dis trict selector 102 take place in positions 1 to 9inclusive of the sequence switch while those of the switching apparatusto which the district selector has access, take place with the districtselector sequence switch in position 10. When the selections have beencompleted, indication ofthis is returned to the sender which advancesthe district selector sequence switch from positionlOto position 12. Assoon as the sequence switch leaves position 10, a circuit is closedfrom-battery, through the windingof relay 103, lower contacts ofsequence switch cam 10%, lower back contact ofrelay105, upper backcontact of relay 112, to ground at'the back contact of relay 300. Thiscircuit also extends to ground at the back contact of relays 400 and 450so that should relay 300 be operatedbecause of a failure of theidentification circuit, as will be described hereinafter, relay 103will-nevertheless be operated. Relay 103' looks over its lower frontcontact and the back contact 7 of relay112 to ground at the back contactof relay 300, thus rendering itselfindependent of the sequence switchand 1 of relay 105. 'Relay103 in operating closes a circuit frombattery, through its upper front contact,'lower winding of relay 106,lower back contact of relay 301, lower back contact of relay 302,winding of relay 303,

lower back contact of relay 304, to ground. Relay 106 operates, lockingthrough its upper winding and over its upper front contact,

, innerback contact of relay 305, winding of relay 304, upper backcontact of relay 302 to ground. The closure of the upper contact of"nect network 310 in parallel with 'aportion of the talking circuit,namely, thatpart passing through the contacts of relay 105. Thesecircuits may be traced :from the tip brush of the line finder, fourthcontact of relay 107, upper back contact of relay 306to the upper rightterminal of thenetwork, through the upper retardation coil,uppermostback contact of relay 311, upper back contact of relay 307,sixth contact of relay 107, to the tip conductor of the talking circuitat a point beyond the-contact of relay 105 from the ring brush of theline-finder, third contact of relay 107 inner back contact of relay 306,to the lower right terminal of thefnetwork'310, lower retardation coil,middle back contact of relay 311, through the winding of relay 312,inner back contact of relay 307, fifth contact of relay 107 to the ringconductor at the right of the contact of relay 105. By the sameoperation the lower'winding of relay 315 is bridged across the repeatingcoil of the district selector completing a circuit from battery throughthe lower left winding of repeating coil 108, inner upper back contactof relay 109, fifth contact of relay 107, inner back contact of relay307, upper normal contact of relay 316, lower winding ofrelay 315, upperback contact of-relay 307, sixth contact of relay 107, upper "backcontactof relay 109, upper left winding of repeating coil 108 to ground.-Relay 315 operates in this circuit and initiates the testing .of thecalling line. The operation of relay 315 com pletes a circuit fromground at its upper T front contact, inner backcontact ofrelay 309,

middle lower front'contact of relay 106, up per windingofrelaytobattery. Relay 105 operates, opening the talking circuit atitscontacts and thus introducing thenetwork 310'into the talking circuitso that the subsequent test may produce no unpleasant clicks or othernoises to disturb the conversation.

i/Vith the inclusion of the networkin the talk ngclrcuit relay 312 isIIIClLlClQCllII a circuit fed by battery through the repeating coil 108and extending over the subscribers line. in which circuit relay 312operates provided the conductors connecting the identificationv circuitand the district selector as well as the subscribers line areuninterrupted.

Thec'losure of the locking circuit of relay 106 causes the operation ofrelay 304L- which V in turnoperates, relay 301 to prevent the 240 has apolarized relay and a grounded transfer of the call to anotheridentification circuit. Relay 304 also closes a circuit over its lowerfront contact, lower back contact of relay 313, winding of relay 314 tobattery, preparing a timing circuit for determining whether the testsare completed properly. It also connects ground over conductor 320 tothe armature of relay 312.

Assuming that relay 312 operates, a circuit is closed from battery,through the winding of relay 313, lowermost back contact of relay 311,contact of interrupter 317, front contact of relay 312 to groundedconductor 320. Relay 313 looks through the winding of relay 311, overthe upper front contact ofrela 313-to grounded conductor 320. Belay 311does not operate until interrupter 317 opens its contact to open theshunt around the winding of relay 311. WVhen relay 311 operates thesubscribers line is disconnected from therepeating coil but relay 315remains bridged across the repeating coil holding the connection. Thetwo sides of the subscribers line are then extended over the upper frontcontacts of relay 311 and the back contacts of relay 318 to the windingof relay 319 and battery, to determine whether the calling party is oneidentified by ground.

Examining Fig. 2 for a moment it will be apparent that each party 210,220, 230, and

contact associated with the substation. With the receiver removed fromthe switchhook the substations 210 and 220 are not grounded whilesubstations 230 and 240 have ground connected through the winding of thepolarized relay to the line. In the case of substation 230 the groundextends over an auxiliary contact of the switchhook, back coni tact ofpolarized relay 231, retardation coil 232 v upper winding of polarizedrelay 231, through the switchhook, transmitter and dial contact 236to'the ring conductor, and

through both windings of the polarized rej lay and one winding of thesubstation repeating coil to the tip conductor. In the case ofsubstation 240 the ground extends over the auxiliary contact of theswitchhook, back contact of relay 241, retardation coil 242, up-

.per winding of relay 241, left winding of coil 24-1'to the tipconductor while it extends through both windings of the polarized re-.lay through the switchhook, transmitter and dial contacts to the ringconductor. Since l .the subscriber at substation 220 was assumed to becalling ground will not be connected to eithertip or conductor and relay319 will not be operated, It should be noted that the battery connectedto relay 319 is the re- .verse'of that used elsewhere so that it has noeffect onthe polarized relays at the substations.

V, conductor 320, middle front contact of reoperates and looks throughthe winding of relay 0 and the lower front contact of relay 318 togrounded conductor 320 but relay 322 does not operate until interrupter317 opens its contact. VJhen ground was connected to conductor 320 acircuit was also closed over the lower back contact of relay 318 to thevinding of relay 326 and battery. Therefore, the operation of relay 318extends the tip conductor of the subscribers line over the front contactof relay 311 front contact of relay 318, back contact of relay 322, tothe upper winding'of relay 323 and battery and in parallel throughresistance 341 and the inner upper front contact of relay 326 tobattery. It also extends the ring conductor over the middle frontcontact of relay 311, inner upper front contact of relay 318, innerupper back contact of rel y 322, through the lower winding'of relay 323,to battery 325, through lamp 324 and in parallel with the winding ofrelay 323, through resistance 342 and the upper front contact of relay326. Battery 325 is the usual coin battery and has a value ofapproximately 110 volts while the battery connected to the upper windingof relay 323 1'7 is approximately volts. T he net result of the use ofthese two batteries is the same as though one 50 to volt battery wereconnected to the side of the line to which the coin battery isconnected. The purpose served by using the two batteries will beapparent hereinafter. The operation of relay 318 opens the circuit ofrelay 326 which is slow to release and, therefore, after a shortinterval opens the shunts closed through its contacts around thewindings of relay 323. This, therefore, permits the polarized relay inthe substation to operate, if it is going to, before relay 323 becomeseffective. In the present case polarized relay 221 operates since it isso connected and polarized as to respond to negative battery applied tothe ring conductor. Vhen relay 221 operates it connects ground over theauxiliary switchhook contact, front contact of relay 221, through retardcoil 222, upper winding of relay 221, contact 226, transmitter 225, dialcontact 224 to the ring conductor. It also connects ground over theswitchhook contact, front contact of relay 221, retardation coil 222,both windings of polarized relay 221, winding of repeating coil. 227 tothe tip conductor. Therefore, when relay 326 releases opening the shuntsaround the windings of relay 323, this ground imbalances the circuit ofdifferential relay 323 so that the relay operates and closes a circuitfrom ground, over its front contact, inner back contact of relay 308,innermost lower front contact of relay 106, winding of relay 109 tobattery. Relay 109 loo f operates and locks over sequence switch cam ofrelay 311,318, and 322, the upper winding 110 to ground. 7 It is to benoted thatthe windings ofrelay 323 are so proportioned that the currentflowing through them from 110 volt battery 325, over a loop at thesubscribers substation, to central olhce battery connected to the upperwinding of relay 323 maintains therelay unoperated whereas with groundconnected to the circuit at the substatiom-the current through onewinding is reversed and results in the operation of the relay. The sameholds'true ofrelay 327.

8 At the time that relay 326 was operated a circuit was closed frombattery, through the winding of relay 328, inner lower back contact ofrelay 322 to grounded conductor 320. Therefore, when relay 322 operatesfollowing the opening of the contact of interrupter 317, the tipconductor of the calling line is GX- tended over the outer upper frontcontacts of relay 327, and in parallel therewith through resistance 343and the upper front contact of relay 328, through lamp 324 to 110 voltbattery 325. The ring conductor is extended over the inner uppercontacts of relays 311,318 and'322 to central office battery through thelower winding of relay 327 and in parallel therewith throughresistance344 and the inner front contact of relay 327 to central ohice battery.As in the case ofrelay 323 relay 327 cannot operate with its windingshunted in this manner. The operation of relay 322 opens the circuit ofrelay328 and. when this relay releases after an interval the windings ofrelay 327 are connected directly to the line. Since the polarized relay221 responds only to battery over the ring conductor it does not'operateat this time and, therefore, does not connect ground to the line,

leaving relay 327 unoperated.

The next closure of the contact of interrupter 317 completes a circuitfromconductor 320, front contact of relay 313, contact of interrupter317,. innermost front contact of relay 311,.back contact of relay 321,lower-' n ost'front contact of relay 322, winding of relay 316 tobattery. Rela 316 operates and locks to conductor 320.. It also connectsground from conductor 320, over its inner-' mos-t lower contact to thewinding of'relay 313, holidi'ng that relay operated but shuntmg relay311 which releases restoring the connection between the repeatingcoil108 and the calling'line. Relay 312 reoperates. Relay 316 also closesacircuit from battery, through the winding of relay 314, lower frontcontact, of relay-315, lowermost front contact of re lay 316 tocroundedconductor 320. The op-.

eration of relay 312 opens the locking circuit ofrelay 315 and theoperation of relay 316 connects resistance 329 in parallel with the 7 7operating'winding of relay 315, thus releasing relay315. The release ofrelay 315'opens V, the circuit of relay, 105 and that relay releasesrestoring the talking circuit to itsnormal condition. I The release ofrelay 315 also opens the circuit of relay 314. The reclosure of thetalking circuit shunts the winding of relay 312 which now releases. Acircuit is now closed from battery, through resistance 111, winding ofrelay 112, lowermost front contact of relay 106, upper back contact ofrelay 309, upper back contact of relay 315, innermost front contact ofrelay 313, back contact of relay 312 to grounded conductor 320. Relay112 locksover-its inner upper front contactto ground over cam-110. Theoperation of relay 112 opens the locking circuit of relay 103 and'thatrelay releases in turn releasing relays 106 and 107, followed by therelease cfrelay 304. The release of relay 304 disconnects ground-fromconductor 320, thus releasing relays 313, 316, 318, 322 and 301. v

VVhenth-e called subscriber answers polarized relay 113 operates in thewell known manner. .A/CllCLlle is thereupon completed froin'ground, overcams 114 and 115, front contact ofrelry 113, earn 116, left contact ofinterrupter117, windingof relay 118 to battery. Relay 118 operates andlooks over canis- 119 and 116,front contact of relay 113, came 115 and114 toground. When interrupter 117 closes its right hand contact acircuit is closed from ground as previouslytraced, over the inner upperfront contact of relay 118, cam 120, winding of relay 121 to battery.Relay 121 locks over its upper front a operated a circuit is closed frombattery, over the lower front contact of relay 121,-inner lower frontcontact of relay 112, upper winding of relay 122, winding of relay 250,back contact of relay 251, back contact of relay 252 to ground, assumingthat the meter control circuit is idle. Belay 250 operates .momentarilv,but relay 122lockst1rough its lower winding and front contact to thewinding of relay 252 which onerates opening the energizing circuit forall relays-such as relay 122 and releasing relay250. Relay 252 alsocloses a circuit from ground, through its front contact, windin r ofrelay .251 to battery.

from ground at the front contact of relay 252, inner left frontcontactof relay 251, middle upper front contact of relay 122, al-j Relay 253 isone of four party relays each i of which is individual toone of the fourparties connected to a party line. For exthe line finder Relay 251operates andcloses a circuit ample, relay 253 is individual to thesecond party and relay 237 is individual to the third party. The linefinder and district selector of Fig. 1 is arranged to serve a maximum offour hundred lines. As will appear hereinafter these lines may be eitherindividual lines or party lines. If all of the lines served by this 2finder are party lines, it is necessary that each party relay preparecircuits for four hundred meters. Consequently, each party relay isarran d to operate ten multi Contact relays each of which in turncontrols forty contacts. here individual lines appear on the same linefinder frame with party lines, the corresponding contacts of the multicontact relays need not be equipped. The operation of relay 253,therefore, by operating the multi-contact relavs 254, 255, etc.,prepares circuits for all of the second party meters belonging to theparty lines served by the district selector of Fig. 1.

The operation of relays 255 and 254 closes a circuit from ground, overtheir right front contacts, right back contact of relay 256, right backcontact of relay 257, winding of relay 258 to battery. Relay 255 alsoprepares a circuit from ground through the winding of message register223, outer left front contact of relay 255, back contact of line relay100 (which is 110w deenergized having been released by the operation ofcutoff relay 125 when the line was found in the well known manner), tothe metering terminal 126 of the calling line. The circuit may befurther traced over the line finder brush, uppermost front contact ofrelay 122, inner right front contact of relay 258, winding of relay 259to battery. Relay 259 operates for a purpose which will be describedhereinafter. The operation of relay 258 also closes a circuit frombattery, through the winding of relay 260, middle front contact of relay258, left contact of interrupter 261. .l Vhen interrupter 261 closesthis circuit relay 260 operates, looking over its inner front contact toground at the front contact of relay 252. lVhen interrupter 261 closesits right contact it completes a circuit from ground, over the uterfront contact of relay 260, innermost upper front contact of relay 122,resistance 111 and battery. This shunts the winding of relay 112 andthat relay releases opening the circuit of relay 122 in turn releasingrelay 252, and restoring the meter control circuit to normal. Since theoperating circuit of relay 112 was closed through the contact of relayl06,which is now released, it is impossible to make a second char eirrespective of the length of the conversation although it is obviousthat there is nothing in the present inventive idea Hadthe subscriber atsubstation 230 been calling the removal of his receiver would haveconnected the ground over contact 238, back contact of relay 231,retardation coil 232, upper winding of relay 231, switchhook contact234, transmitter 235, dial contact 236 to the ring conductor and throughboth windings of relay 231, left winding of the repeating coil to thetip conductor. zi lion therefore, relay 319 is connected to the tip andring conductors as above described this relay operates. Relay 319 inoperating closes a circuit from ground through the winding of relay 321,contact of relay 319, upper back contact of relay 305, innermost contactof relay 107, through the winding of relay 124 to battery. Batterythrough resistance 330 is connected in parallel with relay 124, thusinsuring the operation of relay 321. WVhen relay 124 operates and locksover its inner upper front contact and the bot-tom contact of cam 110,this locking ground is connected in shunt of resistance 330 and battery,releasing relay 321. l/Vith relay 321 operated the interrupted groundcontrolled by interrupter 317 is transferred from the winding of relay318 to the winding of relay 310 so that if relay 124 does not operatebefore the next closure of interrupter 317, the identification circuitwill be dismissed and no registration will be set up in the district,resulting in a free call.

If the registration is made correctly the remaining tests are made asabove described. Relay 231 is polarized to respond to battery connectedto the ring conductor. Therefore, when relay 318 operates connectingbattery 325 to the ring conductor, relay 231 operates disconnecting theground at its back contact from the line. When relay 326 releasesopening the shunt around the winding of relay 323 the current flowthrough that relay prevents its operation. WVhen battery 325 isconnected to the tip of the line by the operation of relay 322, relay231 does not operate and the ground remains connected. to the line.There fore, when the shunts are removed from relay 327, this groundcauses the operation of relay 327 closing a circuit from ground, overthe front contact of relay 327, upper back contact of relay 308, secondfront contact of relay 107. winding of relay 123 to battery. Relay 123locks over its inner upper front contact to the lower contact of 110.When the registration equipment functions the meter selecting circuitmay be traced from ground, over the outer right front contact of relay258, inner left front contact of relay 251, middle upper front contactof relay 122, normal contact of relay 109, upper front contacts ofrelays 123, and 124, winding of relay 237 to battery. Relay 237 operatesand connects the third party meter 233 to the metering terminal of theline ready to receive metering potential as previously ground to theline, relay 319 is operated in the manner described for substation230 inturn operating relay 124. Relay 241 does not respond to heavy batteryconnected to the ring conductor and, therefore, the ground which remainsconnected to the line operates relay 323 in turn operating relay 109.'Relay 241 does-respond to battery connected to the tip conductor, andremoves the normal ground thereby preventing the operation of relay 327.

To summarize:

If substation 210 calls, registration relay 123 operates. I

If substation 220 calls, registration relay 109 operates.

Ifsubstation 230 calls, registration relays 124 and 123 operate. .7

If substation 240 calls, registration relays '124 and 109 operate. Relay109 serves the added purpose of reversing the direction of current flowthrough the substation so that the ground Will be re moved from the lineduring conversation. In-the case of substation 220 it prevents theoperation of relay 221 While in the case of substation 240 it causes theoperation of relay 241 to remove the ground.

The meter control equipment is especially arranged so that it'ispossible to place party lines and individual lines on the same frames,so far as metering is concerned. An individual line Will not be providedWith a polarized relay, grounded contact and a choke coil such asshownin connection with the'party line. Since there is no ground. at anypoint of the test none of relays 109, 123 or 124 is operated. The meterselecting circuit extends from ground over the front contact of relay252, inner left front contact of relay 251, middle front contact ofrelay 122, normal contact of relay 109, upper back contact of relay 123,upper Winding of relay 127, windings of relay 256 to battery. Relay 256operates and closes a circuit from battery, 7 through the Winding ofrelay 258, right back contact of relay 257 to ground at the outer rightfront contact of relay 256. It also closes a circuit from battery,through the inding of relay 259, inner front contact of relay 258,uppermost contact of relay 122, to the metering terminal of theindividual line, over the back contact of the line relay (not shown) andthe \v1nd1ng of message rc Relay 258 also'prepares a circuit from bat-Igister 202 to ground.

tery, through the Winding of relay 260,1niddle front contact of relay258, to the left 'contact of interrupter 261-. When interrupter 261closes that contact relay 260. operates and locks to ground at the outerfront Contact of relay 258. Relay 260 prepares a circuit from ground,over the right contact of interrupter =261, outermost contact of relay260, inner the identification equipment, the Winding of relay 127 isintroduced in the circuit of relay 256 as above described. If the lineis an individual line the message register Will be connected directly tothe metering terminal and relay 259 Will operate in series therewith. Ifthe lack of registration is due to faulty functioning relay 259 cannotoperate. Therefore, When relay 260 operates battery is connected overthe back contact of relay 259,middle front contact of relay 260, inshunt of the high resistance Winding of relay 256, thus reducing theresistance in series With relay 127. Relay 127 is marginalandcannot'operate as long as the high resistance Winding of 7 relay 256is in its circuit. With this Winding shunted relay 127 operatesand'closes a circuit over its lowermost contact, lowermost contact ofrelay 112, to the meter 128. A. record is, therefore, set up of thenumber of times that the eopuipmentv fails to register. This meter iscommon to the district selectors served by the identification equipment.If the number of failures recorded appears excessive, key 129 may beoperated, locking relay 127 and flashing lamp 130 so that the identit yof the district selector may be determined. Belay 127 also opens thecircuit of down drive magnet 131 of the line finder, preventing itsrestoration to normal and thus indicating the line With which thetrouble arose.

Relays 262 and 263 serve to cause an alarm in case the meter controlcircuit does not operate properly. Battery is intermittently connectedto conductor 264 and thewinding of relay 263 and after a measuredinterval is connected to conductor 265 and the Winding I of relay 262.The circuit of relay 263 extends to ground over the contact of relay 250and the back contacts of relays 251' and 252 if relay 121 does not lock.It extends to ground over the front contact of relay 251 during theselecting and operation of the meters and also extends to ground overthe front contact of relay 257 if the meter connecting relays such asrelays 254 and 255 fail to operate following the operation of selectingrelay 253 or if one of these relays operates falsely in the case of anindividual line. 'VVhen battery is connected to conductor 264 Whileground is connected to the other terminal of relay 263, relay 263operates and looks through its inner front contact as long as theoperating ground continues. If this ground remains long enough, theconnection of battery to conductor 265 operates relay 202 in a circuitextending over the middle front contact of relay 263 to ground. Relaylocks to battery over its inner left front contact and is helo operatedunder the control of relay lVith relay 262 operated a circuit is closedfor one of the 23? or according to which no. operated relay 263 and analarm is operated over conductor 269.

Relay 106 is indivi dual to the district selector and a siin -l relaysuch as relay 132, etc., is provided for each district selector of thegroup sermd by the identification circuit of Figs. 3 and 4:. lfheserelays are arranged in sequence and the locking circuit of any relayextends over the hack contacts of the relays following it in thesequence. Therefore, if two relays operate at the same time only thelower re-la in the sequence can loci; and the other district selectormust await the release of the identification circuit. If, for anyreason, this chain locking circuit is broken so that relay 106, forexample, cannot lock, the operation of relay 303 in the energizingcircuit of relay 106 prepares a circuit from ground, over the frontcontact of relay 303, right contact of interrupter 331, winding of relay332 tobattery. Relay 332 looks over its upper front contact to the frontcontact of relay 303. Relay also closes a circuit from ground, over itsfront contact, lower contact of relay 313, wincin of relay 31a tobattery. If relay 106 looks through the winding of relay 30d the circuitof relay 303 is opened at once and relay 332 cannot operate. With relays332 and 314 both operated the closure of the left contact of interrupter331 completes a circuit from ground at the front contact of relay 303,left contact of interrupter 331, lower front contact of relay 332, frontcontact of relay 314, winding of relay 333 to battery. Relay333 loclrsthrough its lower winding and lower front contact, key 33 1, winding ofrelay 335 to ground, thus oper ating. an alarm which can only besilenced by the operation of key 334;. It also lights lamp to indicatewhich identification circuit failed. Relay 333 also connects ground overits front contact, uppermost back contact of relay 309, lowermostcontact of relay 106, which is operated but not locked, winding of relay112, resistance. 111 to battery. Relay 112 releases relays .103, 106 and303. Since no rep stration was set up the call will proceed as a freecall. If relay. 103 locks, relay 30 1 operaltos in the locking circuit,opening the ci cuit of relay 303. HoweverQrelay 304 substitutes groundat its lower front contact for the ground at the front contact of relay303. Therefore, the line is open so that relay 312 cannot operate, andin turn relay 313 does not operate, relay 31% remains operated. and thealarm operates as abovedescribed.

According to the present disclosure three identification circuits areprovided to serve a large group of district selectors and each of thesenormally serves a particular part of the group. Means has been provided,howe ,so that if one identification circuit fails to function, one ofthe other identification cir its may be used. If the identification doestake place wit-hm a predetcrn'nned time relay 332 is operated under thecontrol of intenupter 331 and locks as above described. 1 1e operationof relay 313 releases relay 314 so that the subsequent closure of theleft contact of interrupter 331 extends ground over the front contact ofrelay 332, back contact of relay 314:, to lamp 337, and winding of relay300 and battery. Relay 300 extends its operating ground over the backcontact of similar relays 100 and 450 of the other identificationcircuits, through the winding of relay 338, key 339, right winding ofrelay 3 10 to battery. Relays 338 and 34.0 operaJe, relay 3&0 soundingan alarm and locking to the alarm circuit. The operation of relay 338connects ground over its front contact to the armature of relay 300,thus holding relay 300 operated when interrupter 331 opens its contact.Relay 300 also closes a circuit for relay 302. Relay 302 opens thecircuit of relay i at its upper back contact and when relay 301 releasescompletes a. circuit over the upper front contact of relay 302, bacl:contact of relay 301, through the windof re ays 305, 306, 307, 308 and309, in parallel to battery. Relays 305 to 309 in oping transfer thecircuits which connect the d strict selector with this identificationcirc the identification circuit shown at the left of Fig. l. Since bothidentification circuits ind cated on Fig. 1 are identically the sar e ast shown in Fig. 3, only the transfer and switching relays have beenshown.

If the second identification circuit should fail to complete itsfunction in. the proper time the some operations will take place and thecircuits further extended to the third identification circuit. In caseall three fail, the operation of relay J0 of the third identificationcircuit opens the circuit of relay 338 and releases relays 300, 400 and450. Calls may also be rerouted from the second lentification circuit tothe third and first and from the third'identification circuit to thefirst and second in. the same way as they were advanced from the firstt0 the third as above described.

If at the completion of the identification tests, relay 312 fails toreoperate, and consequeutly relay 315 does not release, a circuit isclosed for relay 314, over the lower front contact of relay 315, outerlower front contact of relay 316 to grounded conductor 320, thusoperating relay 333 and bringing in an alarm through the operation ofrelay Relay operates relay 112 as before.

circuit merely dismissed.

by associating the district selector with other identification circuits.

l Vhatis claimed is:

1. In a telephone exchange system, a plurality of telephone lines, aplurality of correspondingly designated substations on each line, ameter for each substation on each line, a plurallty of selectors, asingle metering ter- I minal for each line, a called line, means forestablishing a connection to said called line under the control of asubstation on one of said lines including one of said selectors, a

meter control circuit common to said selectors, means controlled by theresponse of said called line for connecting said meter control circuitwith said selector, said connecting means being eflective to render saidcontrol circuit individual to the selector to which it is connected,aset of relays in said control circuit for each designation of saidsubstations, said relays serving to connect the me ters of all similarlydesignated substations with the metering terminal of the line onwhicheach'substation is located, and means responsive to said connectingmeans for operating the set of relays for the designation of thecallingsubstati'on.

2. In a telephone exchange system, telephone lines having a plurality ofsubscribers substations located thereon, a single metering terminal foreach line, a plurality of selector. switches for extenclingsaid line, acalled line, 'means responsive to the extension of a call to said calledline from one of said substations through one of said selector switchesfor testing said line and establishing a record in said selector switchof the calling substation, a meter control circuit, means controlled bythe response of said called line to associate said meter con- I trolcircuit with said selector, means in said meter control circuitresponsive to the record in the selector switch for connecting the corresponding meter of all the lines to which saidselector has access tothe metering terminal of the line to which each meter is individual,andmeans under the joint control of said meter control circuit and saidselector to operate the meter of the calling substation. 7

3. In a telephone exchange system a plurality of party lines, asinglemetering terminal for each line, a meter for each party on said lines, aplurality of selector switches for extending said lines, a called line,means re sponsive to the extension of a call to said called line fromone of said substations through one of said selector switches -forestablishing a record in said selector switch of the calling substation,a meter control circuit, means controlled by the response of said calledline to associate said meter control circuit with said selector, a relayin said control circuit for each party, means to'operate one of saidrelays in accordance with the registration'in said selector, means underthe control of said relay to connect thecorresponding meter of each linewith the metering terminal of that line and means including saidcontrolvcircuit and said selector for applying metering potential to saidcalling'line to operate the meter of said calling party. i

4. In a telephone exchange system, individual lines and party lines, asingle metering terminal for each line, a selector for extendingconnections fromsaid lines, means to test calling lines and to set up aregistra tion in the selector if the calling line is a party line toindicate the party calling, a meter control circuit common to aplurality of selectors, said control circuit comprising means forconnecting a party line meter withthe metering terminal, meansresponsive to the connection of the meter with the metering terminal forapplying metering current to said metering terminal, and means fordiscriminating between party lines and individual lines to render saidcurrent supply means independent of said meter connecting means in thecase of individual lines.

1 5. In a telephone exchange system, individual lines and party lines, asingle metering terminal for each line, a selector for extendingconnections from said lines, means to test calling lines and to set up aregistration of the party calling ifthe calling line is a party line andno registration if the calling line is an individual line, a metercontrol circuit common to a plurality of selectors comprising meansunder the control of the party registration to connect the proper meterwith the metering terminal of a calling party line, and means thereuponeffective to supply metering current to said metering terminal and othermeans effective if no registration is set up in the selector to causethe supply of metering'current to the metering terminal of the callingline.

6. In a telephone exchange system, individual telephone lines; partytelephone lines havingapluralityofsubstations,a selector, means forextending a connection from one of said 1 lines throughsaid selector,means for establishing a record of the calling substation in the case oflines having a plurality of substations and no record in the case ofindividual lines, means to prevent the establishment of any record ifsaid record is not correctly established, a meter control circuit, andmeans in said meter control circuit to discriminate in its operationbetween individual lines and party lines and means to discriminatebet-ween a no record condition due to the calling line being anindividual line and a no record condition due to improper recording.

7. In a telephone exchange system, individual telephone lines, partytelephone lines having a plurality of substations, a selector, means forextending a connection from one of said lines through said selector,means for establishing a record of a calling substation in the case oflines having a plurality of substations and no record in the case ofindividual lines, means to prevent the establishment of any record ifsaid record is not correctly established, a meter control circuit, meansin said meter control circuit to dis criminate in its operation betweenindividual lines and party lines and means to discriminate between a norecord condition due to the calling line being an individual line and ano record condition due to improper recording, and means under thecontrol of said discriminating means to record the number of times thata no record condition occurs due to improper recording.

establishing a record of a calling substation in the case of: lineshaving a plurality of substations and no record in the case ofindividual lines, means to prevent the establishment or" any record ifsaid record is not correctly established, a meter control circuit, meansin said meter control circuit to discriminate in its operation betweenindividual lines and party lines and means to discriminate between a norecord condition due to the calling line being an individual line and ano record condition due to improper recording, means under the controlof said discriminating means to record the number of times that a norecord condition occurs due to improper recording, and manual means torender said discriminating means efiective to indicate the selector onwhich the record was improperly established.

9. In a telephone exchange system, a plurality of party lines, a meterfor each party on each line, a plurality of district selectors forextending said lines, a plurality of identification circuits common tosaid district selectors, a called line, means to establish a connectionfrom a calling line to said called line by means of oneof said districtselectors, means in said district selector responsive to theestablishment of said connection to cause the association of one of saididentification circuits with said district selector, means in saididentification circuit to test the calling line and to set up aregistration in the district selector of the calling party, meanseffective following the establishment of such record to disconnect saididentification circuit from said district selector, a meter controlcircuit, means controlled by the response of said called line toassociate said meter control circuit with said district selector, arelay in said control circuit for each party, means to operate one ofsaid relays in accordance with the registration in the districtselector, a single metering terminal for each line, means under thecontrol of said relay to connect the corresponding meter of each linewith the metering terminal of that line, and means including saidcontrol circuit and said district selector for applying meteringpotential to the terminal of the calling line to operate the meter ofthe calling party.

In witness whereof, we hereunto subscribe our names this 28th day ofMay, 1929.

WARREN W. CARPENTER. LEWIS H. JOHNSON.

